The invention is concerned with certain novel .beta.-lactams having pharmaceutical utility.
Monocyclic .beta.-lactams (monobactams) illustrated by the formula: ##STR2## are a class of antibacterial agents [see e.g. Tetrahedron Letters 25, 887-880 (1984); Koster et al. ".beta.-Lactam Antibiotics, Chemistry, and Biology"3, 339-375 (1982)].
Novel .beta.-lactams having the formula: ##STR3## have been discovered.